Rider propelled amusement devices of the general type to which the invention relates are well known in the art. In many such devices, a rider's weight shifting motions or push-pull motions are translated into rotation by a series of linkages connected to a center post. Alternative approaches are described in U.S. Pat. No. 2,447,203 (O'Toole) of Aug. 17, 1948, U.S. Pat. No. 3,235,251 (DeShano) of Feb. 15, 1966, and U.S. Pat. No. 3,642,275 (Ellico) of Feb. 15, 1972. In these devices a rider sits, stands, or otherwise supports himself on a rotatably mounted structure above an undulating circular track. A wheel assembly is carried by the rotatable structure so as to be rollable along the undulating track. By applying downward force to the wheel assembly against appropriate portions of the undulating track, the rider causes the wheel to roll up and down the undulating track, thus translating this downward force into rotational motion of the rotatable structure. The downward force can be generated by rocking motion of the rider, through direct application of weight intermittently to the wheel assembly by a foot, through manipulation of a handle, etc. Thereafter it is basically a matter of hanging on for dear life and waiting for the roller assembly to pass on to another descending portion of the undulating track so that a further propelling force can be imparted to the rotatable structure through the wheel assembly. Since a rider cannot generate propelling force when the wheel assembly is passing through an ascending portion of the track, he generally must either rely on his momentum to carry him past this ascending portion, or have another rider in a complimentary position to provide a downward force during the first rider's coasting phase. In different arrangements, the motion of the rider may be pure rotation in a single phase, or this may be coupled with undulating or rocking movement of the rider support structure.
Basically, it is an object of the present invention to provide a rider propelled rotatable riding device which is believed to be a general improvement over earlier such devices, and one which permits a rider to apply weight-shifting force more frequently to propel his rotation, and indeed to permit him to apply this force almost continuously.
In keeping with my invention, the device comprises two similar, concentrically mounted, circular, vertically undulating tracks formed with peaks and valleys, the tracks being of different radii such that they are spaced from each other as inner and outer tracks. A rotatable rider supporting structure is mounted for rotation concentrically with respect to the tracks, and has coupled thereto a pair of freely rotatable wheels, generally vertically movable, for rolling along the undulating surfaces of respective ones of the tracks. The tracks and wheels are relatively disposed such that each wheel relative to its undulating track is out of phase with the other wheel relative to its undulating track, and preferably this is accomplished by having the undulating tracks substantially 180.degree. out of phase with each other. Rider controlled linkage means are provided for selectively intermittently urging either wheel against its undulating track surface with increased force relative to the other wheel, such that the supporting structure can be rotatably driven by selectively and alternately urging either wheel against a downhill portion of its undulating track relative to the force urging the other wheel against a non-downhill portion of the other undulating track. Preferably the wheels are coupled together by a pivotal link or shaft which is oriented in a generally radial plane, pivotally coupled at its mid-point to the rider support structure for pivotal movement vertically in the radial plane, and coupled to the wheels at its radially inner and outer ends, whereby the wheels are pivotally coupled together for substantially equal but opposite movement in a vertical radial plane as they roll along the vertically undulating tracks. I prefer that the pivotal shaft or link be pivotally coupled beneath the support structure, and that actuating links are coupled to this shaft on opposite sides of its pivot axis and extend upwardly through the support structure such that their upper ends are exposed for rider manipulation vertically. Advantageously, a rider support seat is coupled to the upper ends of the actuating links such that a rider seated thereon can rock radially back and forth and shift his weight from one actuating link to the other so as to alternately relatively urge either link downwardly and decrease the relative downward force on the other link. Typically a plurality of such seats with their associated linkages and wheels will be provided at equally spaced intervals about the periphery of the rotatable support structure. The assembly of the lower pivotal shaft or link, the upright actuating links, and the rider seat may resemble and function as an adjustable or variable parallelogram, and additional cross-links may be coupled to the upright links and to the rider support structure for increased strength and stability. The wheels themselves may be mounted rotatably on the lower pivotal shaft or link, in which case they will lean inwardly and outwardly with the pivotal movement of the pivotal shaft, or they may be rotatably mounted on stub shafts carried by the lower portions of the upright actuating links, in which case they will remain substantially vertical, but will vary slightly in horizontal distance from each other. The device can be easily fabricated with sufficient clearance or play as to accommodate either arrangement.
Other features and advantages of the invention will be set forth in or apparent from the ensuing description of a preferred embodiment of the invention, taken with reference to the accompanying drawings.